Actuating device with push buttons

ABSTRACT

An actuating device is provided for a technical system, especially for selecting gears of a shift-by-wire speed-change gear. This includes a push button arrangement with at least one push button ( 1 ) as well as a device ( 4 ) generating electrical control signals for transmission to the technical system. The actuating device has a separately controllable blocking device ( 2, 3 ), each associated with at least one push button or all push buttons of the actuating device. The blocking device ( 2, 3 ) mechanically blocks the particular push button ( 1 ) and can be driven by auxiliary energy. This provides an unambiguous tactile feedback on the state of the system or the admissibility of the shifting operation when the push buttons are pressed. Hazards that arise from unrecognized states of the system, inadmissible shift commands or operating errors, defects on the system or non-functioning signal transmission between the actuating device and the system are eliminated.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a United States National Phase application ofInternational Application PCT/DE2005/002009 and claims the benefit ofpriority under 35 U.S.C. § 119 of German Patent Application DE 10 2004054 617.7 filed Nov. 11, 2004, the entire contents of which areincorporated herein by reference.

FIELD OF THE INVENTION

The present invention pertains to a device for actuating a technicalsystem with a push button arrangement.

BACKGROUND OF THE INVENTION

Actuating device of this class are used, for example, but by no meansexclusively, for manually selecting gears or for gear preselection inspeed-change gears of motor vehicles.

The gear is preselected or the operating state of the vehicletransmission is controlled now in an increasing number of motor vehiclemodels by means of electrical or electronic signal transmission. Anelectrical or electronic actuation of technical systems ortransmissions, which makes do without mechanical connection in thismanner, does, however, entail that the operator or the driver has, ingeneral, no feedback whatsoever on the execution of a control commandand optionally also no feedback on the fact that his actuating commandmay not be admissible, contrary to operation by means of the prior-artmechanical actuating device.

It may rather happen in actuating device with push buttons and withelectrical or electronic signal transmission that the system or vehicletransmission to be controlled does not assume the operating stateassociated with the pressed push button for certain reasons after one ofthe push buttons of the actuating device has been pressed. In otherwords, this means that the desired state of the controlled system, forexample, of the vehicle transmission, which state is selected bypressing the push button, does not agree with the actual shifting stateof the system or transmission. Such a divergence between the actualoperating state of a technical system and the controlcommand—presumably—entered with the controlling push buttons may havevarious causes.

In the case of the example of the control or gear preselection on anautomatic transmission of a vehicle, motor vehicles equipped withautomatic transmission are frequently provided with a so-calledshiftlock function. Especially the shift positions “D” and “R” can beselected from the neutral position “N” in a vehicle with shiftlockfunction only when the brake pedal is pressed at the same time. This isused for safety and shall prevent a gear from being engaged with theengine running, for example, by inadvertently striking the gear selectorlever of the transmission and the vehicle from coming into motion in anuncontrolled manner.

However, in case of an electrical or electronic push button control of ashift-by-wire vehicle transmission, which is provided with a shiftlockfunction, the driver could select, for example, the shift position “D”by pressing the corresponding push button when the brake pedal is notpressed. However, since the brake pedal is not pressed in the case ofthe example, the transmission remains in the neutral position “N”without any change because of the shiftlock function, whereas the driverbelieves after pressing the push button “D” that the corresponding gearis now engaged.

As a result, this situation leads to a potential safety risk, becausethe vehicle may inadvertently roll backwards on a slope in such a case,or the driver may not leave a hazardous situation quickly enough in thefalse belief of having engaged the Drive gear.

Furthermore, there also may be, for example, a malfunctioning ornon-functioning transmission of the control commands between theactuating device and the system or vehicle transmission controlledtherewith, with the consequence that the gear preselected by the driveron the actuating device is not recognized by the system and thecorresponding control command is thus not sent to the transmission.

A hazardous situation of this type is given in case of the pushbutton-controlled actuation of a motor vehicle transmission, forexample, when the driver brings the vehicle to a stop after driving withthe gear “D” engaged and selects the shift position “P” for the parkingbrake with the engine running. However, the Drive gear “D” continues tobe engaged if the signal transmission is not functioning between theactuating device and the vehicle transmission, without thenon-functioning signal transmission being communicated to the driverduring his attempt at engaging the parking brake. If the driver nowleaves the vehicle in the belief that he has engaged the parking brake,the vehicle will set automatically into motion because the gear isactually still being engaged.

SUMMARY OF THE INVENTION

Against this background, the object of the present invention is toprovide a means for the push button-controlled electrical or electronicactuation of a technical system, for example, a speed-change gear, withwhich the drawbacks of the state of the art can be overcome. Inparticular, the actuating device shall make possible an unambiguoustactile feedback on the state of the system or the shifting operationwhen the push buttons are pressed. Furthermore, the risk of states ofthe system that are not recognizable to the operator in case ofunacceptable shift commands or incorrect actuations, in case of defectsin the system or in case of non-functioning signal transmission betweenthe actuating device and the system shall be eliminated as well.

The actuating device according to the present invention comprises, in amanner primarily known per se, a push button arrangement with at leastone push button. Furthermore, the actuating device has means forgenerating electrical control signals for the transmission of a shiftcommand to the technical system being controlled.

However, the actuating device is characterized according to the presentinvention in that a separately controllable blocking means is associatedwith at least one push button, but preferably with all existing pushbuttons, for mechanically blocking the push button. The blocking meanscan be driven by means of auxiliary energy.

In other words, this means that the push button used to actuate thetechnical system or the plurality of push buttons of a push buttonarrangement for controlling the technical system can be blockedindividually by means of a blocking means each.

The problems described in the introduction, which occur in case of thecontrol of technical systems by means of electrical or electronicsignals, for example, in electronically controlled automatictransmissions, are eliminated in this manner.

Because of the possibility of blocking the push buttons of the actuatingdevice individually, e.g., shift commands that are not admissible basedon the instantaneous state of the system cannot be blocked, as in thestate of the art, only by the fact that such inadmissible shift commandsare simply ignored by the system. Thanks to the individual blockabilityof the push buttons, it can be signaled to the operator or the driver ofa motor vehicle immediately and directly in a tactile manner that theshift command he wishes to implement is currently unavailable or cannotbe momentarily implemented by the system.

Blocking of the push button and optionally of all push buttons of theactuating device may likewise take place thanks to the controllableblocking means, for example, in case of a total failure of the entiresystem, or in case of failure of the signal transmission from theactuating device to the controlled system. It is thus unmistakablysignaled to the operator or driver that it is currently impossible tocontrol the system or to actuate the automatic transmission. Thehazardous situations described in the introduction can thus be avoidedwith a high level of certainty.

The present invention is embodied independently from the design of theblocking means and its arrangement in the area of the push buttonarrangement, as long as reliable blocking of the corresponding pushbutton is ensured with the blocking means.

According to a preferred embodiment of the present invention, theblocking means is designed, however, such that the particular pushbutton is blocked if auxiliary energy is not present for operating theblocking means. In other words, this means that the unblocking of theparticular push button takes place by applying the auxiliary energy,whereas the push button is automatically blocked in case of any failureof the auxiliary energy to ensure a “fail-safe system.”

The type and origin of the auxiliary energy are not essential accordingto the present invention. According to a preferred embodiment of thepresent invention, the blocking means is actuated, however,electrically, preferably by means of an electromagnet. The activelycontrolled blocking of the push button can thus be designed as a simple,inexpensive blocking of a robust design.

The present invention can be embodied independently from the position inwhich the push button can be blocked by means of the blocking means.According to an embodiment of the present invention, the push button canbe blocked by the blocking means in the elevated, i.e., non-pressedposition of the push button. An immediate tactile feedback can thus beobtained for the operator due to the resistance of the blocking meansbecoming perceptible in case of the attempt to press a blocked pushbutton.

However, provisions are made according to another, alternativeembodiment of the present invention for the push button to be able to bebrought actively into the elevated push button position from the pressedposition of the push button, in which case the push button is preferablyspring-loaded in the direction of the pressed push button position.

In other words, this means that the auxiliary energy of the blockingmeans is used to move the push button from the pressed position into theelevated, non-pressed position and to hold it there with a certainforce. The push button can then be pressed by the operator from thisposition while overcoming the force generated by the blocking means.However, if the blocking of a push button is activated, the auxiliaryenergy of the blocking means of this push button is switched off, andthe push button falls back, because of the spring load, into the pressedposition, in which no actuation of the system by the push button cantake place in this embodiment.

This embodiment has a number of special advantages. For example, adirect optical feedback additionally takes place in this embodiment,besides the tactile feedback, which is likewise embodied here, becausethe operator can recognize in this embodiment of the actuating devicealready by looking at the pressed state of the push button that the pushbutton in question is blocked and the corresponding function ismomentarily not available or cannot be selected, without the push buttonhaving to be touched for this. Furthermore, a possible failure of theactuating device or failure of the auxiliary energy also causes the pushbutton to fall back immediately into the pressed position. The systemfailure is immediately recognizable in this case as well, especiallybecause the actuating device is an actuating device with a plurality ofpush buttons.

According to another embodiment of the present invention, the meanspresent in the actuating device for generating the electrical controlsignals comprise a switching means, a separate switching means with asignal transmitter being preferably associated with each push button toensure the reliability of the actuating device.

According to another preferred embodiment of the present invention, theswitching means associated with a push button comprises more than onesignal transmitter, preferably two or four signal transmitters, whichare preferably arranged in parallel.

The use of two signal transmitters per push button has the advantagethat even the failures of a switching means designated as so-calledsimple errors can be recognized with it for increased failure safety orredundancy, because different states of the two signal transmitters,which states are not admissible or do not occur in satisfactoryoperation, are thus recognized in case of the failure of one of the twosignal transmitters of one push button. However, which of the two signaltransmitters has failed or which of the two signal transmitters is nowreporting the correct state corresponding to the position of the pushbutton cannot yet be recognized with two signal transmitters per pushbutton. Even though the malfunctioning push button can thus beidentified with two signal transmitters per push button, the actualswitching state of that push button cannot be recognized.

If four signal transmitters are used per push button, both simple errorscan be recognized and the instantaneous position of the push button canstill also be identified at the same time, because three signaltransmitters still assume a value that is identical for these three evenin case of failure of one signal transmitter and furnish a reliableindication of the actual state of the push button despite the failure ofone signal transmitter. Even though the so-called twofold errors, whichare, however, much more unlikely, can also be recognized with foursignal transmitters, the actual switching state of the push button is nolonger identifiable in this extremely rare case, analogously to thesimple error in case of two signal transmitters being present per pushbutton.

The principle of operation according to which the at least one signaltransmitter operates concretely is not relevant now at first as long asa sufficient number of switching cycles as well as sufficient robustnessand vibration resistance are given. However, the signal transmitter isdesigned as a microswitch according to a preferred embodiment of thepresent invention.

The use of microswitches is advantageous insofar as these are in theform of inexpensive and robust standard components and, moreover,withstand an extremely high number of switching cycles withoutmaintenance.

According to other preferred embodiments of the present invention, theespecially inexpensive and robust switching mats known from the area ofinput keyboards or, depending on the profile of requirements imposed,even magnetically operating Hall sensors or optical sensors are used assignal transmitters.

According to another embodiment of the present invention, the actuatingdevice comprises, furthermore, a device for the mechanical unlocking ofthe blocking means. This unlocking device is available as a so-calledoverride function for the case of malfunctions of the drive of theblocking means. Thus, the unlocking device makes it possible, in theform of a manual mechanical unblocking of the blocking means, forexample, in case of failure of the blocking means, that the actuatingelement can nevertheless be actuated in the sense of an emergencyoperation.

The present invention will be explained in more detail below on thebasis of drawings showing embodiments. The various features of noveltywhich characterize the invention are pointed out with particularity inthe claims annexed to and forming a part of this disclosure. For abetter understanding of the invention, its operating advantages andspecific objects attained by its uses, reference is made to theaccompanying drawings and descriptive matter in which preferredembodiments of the invention are illustrated.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a schematic isometric view of an embodiment of an actuatingdevice for a vehicle transmission;

FIG. 2 is a schematic sectional view of the actuating device accordingto FIG. 1 as a cross section along one of the push buttons;

FIG. 3 is a view corresponding to FIG. 1 of the actuating deviceaccording to FIGS. 1 and 2 with the housing not shown and with thedirection of view towards the blocking means; and

FIG. 4 is a view corresponding to FIG. 3 and a view of the actuatingdevice according to FIGS. 1 through 3 with the direction of view towardsthe electrical signal transmitters.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings in particular, FIG. 1 shows an isometric viewof an embodiment of an actuating device according to the presentinvention. This embodiment is an actuating device for an automatictransmission of a vehicle.

Four push buttons 1, which are associated with the four selectable gears“P,” “R,” “N” and “D” of an automatic transmission, can first berecognized in the view in FIG. 1. One of the gears is selected here bypressing the corresponding push button 1.

In addition, the actuating device according to FIG. 1 also has, however,four electromagnets 2, an electromagnet 2 being associated with each ofthe push buttons “P,” “R,” “N” and “D.” The electromagnets 2 are used toactuate the blocking means of the individual push buttons “P,” “R,” “N”and “D.”

The design and the mode of action of the blocking means appear from thesectional view according to FIG. 2. One of the push buttons 1 as well asthe electromagnet 2 associated with that push button 1 are againrecognized at first. The push button 1 is shown in FIG. 2 in thenon-pressed, elevated position, in which it is held by the coil spring 5in the otherwise neutral state. The electromagnet 2 has a mobilearmature, not shown, which is connected to a locking pin 3. The magneticcoil and the armature of the electromagnet 2 are arranged here such thatthe armature and the locking pin 3 are moved to the right relative tothe drawing when current is flowing through the coil (not shown) of theelectromagnet 2, whereas the armature and the locking pin 3 are alwaysin their left end positions relative to the drawing because of a spring(likewise not shown) in the currentless state of the electromagnet 2.

In other words, this means that the push button 1 is blocked in thecurrentless state of the electromagnet 2 because of the extended lockingpin 3 and cannot therefore be pressed by the driver. At the same time,this causes that the microswitch 4 cannot be actuated, either, and noelectrical switching signal can thus be generated and transmitted to thevehicle transmission, either.

However, as soon as the control circuit of the actuating device or thetransmission control releases the push button 1 and the gear that can beselected therewith, electrical voltage is sent to the electromagnet 2,as a result of which the armature and the locking pin 3 move to theright relative to the drawing and thus release the path for the pushbutton 1 downwards.

The driver can now press the corresponding push button 1, as a result ofwhich the microswitch 4 is actuated and a corresponding electricalsignal is generated and transmitted to the vehicle transmission or tothe transmission control.

FIGS. 3 and 4 show once again the entire mechanism of the actuatingdevice according to FIGS. 1 and 2 in an isometric view and fromdifferent directions of view, the housing being faded out in the viewsin FIG. 3 and FIG. 4.

It is clearly recognized that an electromagnet 2 with a locking pin 3,as well as a microswitch 4 and a resetting spring 5 each are associatedwith each push button 1. FIGS. 3 and 4 show, in particular, the simpleand extremely robust design of the actuating device according to thepresent invention, which comprises, on the whole, only a small number ofbasic elements having a simple design. This is advantageously favorablefor inexpensive production, a correspondingly high operationalreliability and long service life of the actuating device.

The table below shows, furthermore, an example of a switching logic,which can be associated with the exemplary embodiment of the actuatingdevice according to FIGS. 1 through 4.

The gray-shaded fields in the left-hand column (column 1) show theinstantaneously engaged gear “P,” “R,” “N” and “D,” whereas the presenceof other general conditions (“brake pressed” or “vehicle speed above aset speed limit”) is entered in columns 2 and 3.

The state of the blocking means of the individual push buttons which isassociated with a combination of general conditions according to columns1 through 3 can be found in columns 4 through 7. For example, all fourpush buttons “P,” “R,” “N” and “D” can be freely actuated when theneutral position “N” is engaged and the brake is pressed at the sametime (line 6), because it is admissible to engage any gear when thesegeneral conditions are present. However, if the brake is not pressedwhen the neutral position “N” is engaged, it is not possible to shiftout of the neutral position “N” and to engage one of the gears “P,” “R”or “D” for reasons of safety (line 5).

By contrast, all push buttons are blocked when an error occurs in thearea of the transmission or the transmission control in order to alsosignal the state of disturbance to the driver in a tactile form (line9).

2 4 5 6 7 1 Brake 3 P R N D Gear pressed v > v_(limit) button buttonbutton button 1 P no released blocked blocked blocked 2 P yes releasedreleased released released 3 R no released released released released 4R yes blocked released released blocked 5 N no blocked blocked releasedblocked 6 N yes released released released released 7 D no releasedreleased released released 8 D yes blocked blocked released released 9Case of error blocked blocked blocked blocked

Thus, it becomes clear as a result that thanks to the present invention,an actuating device, which makes possible the especially reliable andlow-error actuation of the technical system or vehicle transmission, isobtained for electrically or electronically controlled technicalsystems, especially for speed-change gears of motor vehicles. Theselection especially of inadmissible shifting sequences or operatingstates is thus prevented in the motor vehicle for operationalreliability and driving safety, and the fact that a corresponding shiftcommand is not admissible or is impossible is signaled to the operatoror driver in a clear tactile or optical form.

Thus, the present invention makes an essential contribution to theimprovement of the safety, ergonomics and operatability of technicalsystems, especially when the present invention is used in the area ofvehicle transmissions.

While specific embodiments of the invention have been shown anddescribed in detail to illustrate the application of the principles ofthe invention, it will be understood that the invention may be embodiedotherwise without departing from such principles.

1. An actuating device for a shift-by-wire speed-change gear technicalsystem, the actuating device comprising: a push button arrangement withat least one push button; a signal means for generating electricalcontrol signals for transmission to the technical system, a separatelycontrollable blocking means for mechanically blocking said push button,said blocking means having a driving energy connection for being drivenby means of auxiliary energy.
 2. An actuating device in accordance withclaim 1, wherein said blocking means is in the blocked state whenauxiliary energy is not present.
 3. An actuating device in accordancewith claim 1, wherein said blocking means is electrically actuateable.4. An actuating device in accordance with claim 1, wherein said blockingmeans is electromagnetically actuateable.
 5. An actuating device inaccordance with claim 1, wherein said push button is blockable by meansof said blocking means in the elevated position of the push button. 6.An actuating device in accordance with claim 1, wherein said push buttonis movable into the elevated push button position from the pressed pushbutton position by means of said blocking means.
 7. An actuating devicein accordance with claim 6, wherein said push button is spring-loaded inthe direction of the elevated push button position.
 8. An actuatingdevice in accordance with claim 1, wherein the means for generatingelectrical control signals comprise a switching means.
 9. An actuatingdevice in accordance with claim 8, wherein a switching means with atleast one said signal transmitter is associated with each said pushbutton.
 10. An actuating device in accordance with claim 8, wherein theswitching means associated with a push button comprises two said signaltransmitters.
 11. An actuating device in accordance with claim 8,wherein said switching means associated with a push button comprisesfour said signal transmitters.
 12. An actuating device in accordancewith claim 1, wherein said signal transmitter is designed as amicroswitch.
 13. An actuating device in accordance with claim 1, whereinsaid signal transmitter is designed as a switching mat.
 14. An actuatingdevice in accordance with claim 1, wherein said signal transmitter isdesigned as a Hall sensor.
 15. An actuating device in accordance withclaim 1, wherein said signal transmitter is designed as an opticalsensor.
 16. An actuating device in accordance with claim 1, wherein saidactuating device comprises a mechanical unlocking device for overcomingsaid blocking means.
 17. An for selecting gears of a shift-by-wireautomatic transmission speed-change gear technical system, the actuatingdevice comprising: a push button arrangement with a push button; asignal means disposed for actuation by said push button for generatingelectrical control signals for transmission to the technical system; aseparately controllable blocking means for mechanically blocking saidpush button, said blocking means having a driving energy connection forbeing driven by means of at least one of a main vehicle energy sourceand auxiliary energy.
 18. An actuating device in accordance with claim17, wherein said blocking means assumes a blocked state when auxiliaryenergy is not present.
 19. An actuating device in accordance with claim17 wherein said push button is blocked by said blocking means in anelevated position of said push button.
 20. An actuating device inaccordance with claim 17, wherein said push button is brought into theelevated push button position from a pressed push button position bysaid blocking means.